Echinochloa crus-galli (Barnyarn grass)
Image credit: Paul LarsonIdentification tips
Tip #1: to remember the scientific name, the name of the genus comes from the Greek echinos for "hedgehog", chloe or chloa for "grass" and the species comes from Latin crus to "leg/thigh" and gallus to "rooster".
Plant shape
2º Identification tip: look for purple coloring, may be present in the ribs and ends of the leaves, seeds when not ripe may also have purple coloration, as well as the stem, at its base. The plant can become more spread as well as more upright.
Absence of ligule and auricles
3º Identification tip: is the absence of ligule and auricle, do not remember what this is not even!?
# Take a look down here
Adapted image from Debalin Sarangi
Roots
4º Identification tip: the roots do not have a stallion.
Panicles
5º Identification tip: the panicles have hair at their base and the spikelets may have edges, not being a good identification feature.
Seeds
6º Identification tip: the seeds are straw color and a few millimeters in size. It is balloon-shaped, with "beak", when rubbed between the fingers the dried seeds, release the glumes and other protective components easily, and the caryopsis has darker coloration.
Seedlings - the terror of all
7º Identification tip: main characteristic of the seedling is the lack of ligule (easy check) and auricle (difficult to verify)
8º Identification tip: The coloration of the seedling base may also be another indicator in case of doubt and also the leaves are glabrous (hairless).
Extra references:
http://florafinder.com/Species/Echinochloa_crus-galli.php
http://swbiodiversity.org/seinet/taxa/index.php?taxon=2915&taxauthid=1
https://www.iewf.org/weedid/Echinochloa_crus-galli.htm
https://www.minnesotawildflowers.info/grass-sedge-rush/barnyard-grass